16 July 2017, 23:07 | #21 | |
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Of course you have to compromise with the bandwith (I/O and/or memory) that you have on a given Amiga. Better compression would be great, but on lower-end Amigas you don't have enough compute power for any advanced decompression algorithms either. Since everything is so compromised on these old machines, using compression/decompression or just reduced resolution gives pretty similar results IMHO. It would be interesting if the emulator would also simulate different bandwidth configurations, then it would be easier to compare Amiga models. |
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17 July 2017, 00:45 | #22 |
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That is indeed impressive for only 256 colors per frame. The dithering must be perfect for this video. I notice no banding which can be visible with sky using simple dithered 16 bit (565) chunky.
Not using HAM8 would probably make it possible to allow ModePro to promote the video to RTG so many more Amigas could play it at least. Storing and displaying the data in planar is less than efficient even at 8 bit though. I wonder how things would have been different if the Amiga had HSV (originally planned for the Amiga chipset including for HAM which was more useful) or had received chunky with AGA (could have and should have along with being released 2 years earlier). |
19 July 2017, 04:31 | #23 | |
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However, if all that takes to have it in AGA8 (no HAM) then we are done already, because this looks pretty much the same as the HAM8 version (at least for these kinds of videos). |
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19 July 2017, 06:31 | #24 | |||
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http://aminet.net/package/util/cdity/ModePro Quote:
It really depends on what the gfx card supports but most support a pseudo-chunky LUT8 mode. Some gfx cards only support or prefer little endian modes so be careful there (not a problem if reading/writing a byte at a time). CGFX and P96 support most of the common display formats including both big and little endian formats. See the SDK includes for formats supported. Quote:
ModePro could probably convert the AGA8 to RTG 8 bit data but it is nicer and faster not to convert like you said. |
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24 July 2017, 09:13 | #25 | |
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BTW, I will soon upload a new HAM8 video, just need to find a good way to compute the total number of colors - this should be a very high number and I am curious what it is. The sky is indeed interesting to watch&compare in AGA8 and HAM8 videos (thought about your comment, as I inspected the pixels |
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05 August 2017, 11:29 | #26 |
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And here is now a HAM8 video with color count ...
[ Show youtube player ] That's what I was originally aiming for .. enjoy. The video description also contains sizes&color counts of downscaled variants of the same video. AGA8 doesn't look much different, anyways, the fun-part was the HAM8 decoder to compute the color count |
05 August 2017, 14:45 | #27 |
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while i hate the content, the technical part is great
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05 August 2017, 18:04 | #28 |
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The HAM8 video looks more colorful or at least has more brightness variation (I wonder how a HSV HAM8 would have looked). I did notice some minor banding in the sky and on the girls face rarely. There isn't much difference compared to the AGA 8 bit video which is more impressive and looks better, IMO. Maybe the video tools and editing were better on the 8 bit video?
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05 August 2017, 19:04 | #29 |
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05 August 2017, 20:27 | #30 |
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If you are taking creative liberties then you could do SHIRES HAM8 too which should give more room to morph the colours right.
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05 August 2017, 23:46 | #31 | |
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What would be the difference of a HSV HAM8? |
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06 August 2017, 00:11 | #32 | |
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One could actually display the color palette in each frame, simply by having some fixed rectangles of each color reg hardcoded in the HAM8 picture. Same with AGA8. This would make more clear (or flashy <g>) how this works. BTW, the AGA8 hires variant has 464700 different (unique) colors total. |
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06 August 2017, 00:24 | #33 |
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Yeah, it could be interesting just to see how this works out. Now that you say it, in principle png2ilbm allows to convert any size using the HAM (or AGA) conversion, Thus, I could convert a full HD video to "HAM-HD" - and then backconvert it to 24bit and play it (since there is no other way to play it). In the worst case it looks pretty much the same
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06 August 2017, 02:23 | #34 | |
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I expect better transitions around light and perhaps less banding (the color can stay the same while the brightness changes). We don't know for sure without simulating HSV HAM and I don't know that it has ever been done. The HSV HAM idea was taken from expensive flight simulators which Jay Miner had looked at on a tour. When the Amiga chip set was converted to RGB, Jay thought HAM would be much less useful which is why he wanted to remove it. |
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06 August 2017, 09:00 | #35 | ||
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Quote:
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06 August 2017, 10:27 | #36 |
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Would love to see it on a real A500 with fast memory and a real A1200 with fast memory too.
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06 August 2017, 10:42 | #37 |
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06 August 2017, 17:07 | #38 |
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Sure. Software display of 32 bit images compressed with HSV HAM would show us what it looks like in comparison to RGB HAM but that is the easy part. Tools are needed to convert and dither true color images to HSV HAM which don't exist. This is kind of like HAM on the early days of the Amiga where there was hardware support but few creation and conversion tools so it was rarely used. I doubt anyone will bother creating all the software needed to see how good HSV HAM would have been and it is unlikely the bandwidth savings is worthwhile to implement in hardware today, especially without a common standard. The HSV YCbCr color model is used in JPEG and MPEG so there are modern related compression applications which do have hardware support.
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10 August 2017, 07:00 | #39 | |
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10 August 2017, 07:10 | #40 | |
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There is a tutorial for it in Youtube. [ Show youtube player ] |
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